(Please note: These evidences are contingent upon your first repenting of sin, forsaking all wickedness, trusting in Christ for eternal salvation, and allowing Him to translate you out of darkness and into His kingdom of light.)
1. You are in Christ if you are continually being renewed. Those who are "in Christ" do not rest on a one-time conversion experience. Rather, they constantly cry out to be changed and renewed by the Holy Spirit. Their daily prayer is, "Lord, take out of me everything that is unlike You.”
"Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new" (2 Corinthians 5:17). "Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost; which he shed on us abundantly through Jesus Christ our Saviour" (Titus 3:5-6).
2. You are in Christ if you govern your life by the Scriptures. Do you revere and fear God's Word?
"Whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him" (1 John 2:5). The Bible makes it clear: We know we are in Christ if we love and obey His Word.
3. You are in Christ if your faith is mixed with charity. Scripture says if you do not have charity, or unconditional love, you cannot be in Christ.
"Though I have the gift of prophecy, and understand all mysteries, and all knowledge; and though I have all faith, so that I could remove mountains, and have not charity, I am nothing" (1 Corinthians 13:2). Nothing in Greek here means, "I am nothing now nor will I ever be anything." In other words, "Without unconditional love for all, I am a nobody and I will always be a nobody."
You can be a gifted preacher, a powerful evangelist, or an anointed teacher of God’s Word who walks in great faith, but if you do not have love for others, you are nothing.